This invention relates to pop-up irrigation sprinklers, and more particularly, to a new and improved grit protected pressure regulator used in the pop-up stem of such sprinklers.
It has been known in the art to employ with pop-up type irrigation sprinklers a pressure regulator in the pop-up stem of the sprinkler to control and keep constant the pressure at which water from the sprinkler nozzle is ejected into the atmosphere. The use of such pressure regulators is particularly useful with pop-up sprinklers which will be used where the source pressure supplied to the sprinkler may vary over wide ranges, such as typically found in residential applications or where the sprinklers are to be used in hilly terrain. By using a pressure regulator, the sprinkler nozzle will produce a spray pattern which will be substantially constant over a wide range of supply pressures, thereby assuring that optimum sprinkler performance is achieved even though the source pressure to the sprinkler may vary over wide ranges.
One such pressure regulator which has been suggested for use within the pop-up stem of pop-up sprinklers includes a flow seat secured within a lower portion of the stem, and a flow tube which is mounted within the stem for limited reciprocation above the seat. The flow tube, which is typically spring biased and centered within the stem by O-ring type seals disposed about the upper and lower end portions of the tube and which engage the inside sidewall of the stem to seal the space between the outside of the tube and the inside of the stem between the seals, raises and lowers relative to the seat to regulate the water from the source passing through the flow tube to the sprinkler nozzle in response to the inlet water pressure. By controlling the pressure to the nozzle through movement of the flow tube relative to the seat, a substantially constant water pressure at the nozzle can be maintained.
One problem that has been encountered with pressure regulators of this type mounted in the pop-up stem of a pop-up sprinkler is that grit, dirt, sand and other particulate matter carried by the supply water may cause the pressure regulator mechanism to jam and become inoperative. This is particularly true where the sprinkler is operated in sandy soil conditions, such as, for example, are frequently encounted in Florida and other areas where high concentrations of particulate matter may be found in the ground water supplies used for providing irrigation water.
When the water supply is shut off to the sprinkler after use, water will remain trapped within the stem as the stem retracts into the sprinkler housing. As the water drains down through the stem, or if the sprinkler is equipped with a low pressure shut off valve at the base, as is frequently the case and which results in water being permanently trapped within the stem until a new irrigation cycle is initiated, particulate material carried by or entrained within the water will settle out of the water and drop to the bottom of the stem. As the particulate material settles out of the water, it will settle and accumulate on any upwardly facing surfaces it encounters within the sprinkler. It has been found that frequently this will result in the accumulation of particulate material around the seals at the upper end of the flow tube and will cause the flow tube to jam or become clogged and hence, inoperative.
The present invention provides a means for protecting the seals and operating components of a flow tube type pressure regulator mounted in the stem of a pop-up sprinkler against the influx and accumulation of grit, sand, dirt and other particulate matter to prevent the pressure regulator mechanism from becoming jammed or made inoperative.